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1.
Previous studies in this laboratory have demonstrated that the alpha 2-adrenergic agonist clonidine and related drugs can offer significant protection against both the acute and chronic toxicity to soman administration in rats and mice. The purpose of this study was to determine whether addition of clonidine to a standard pretreatment protective regimen against soman toxicity could offer added protection or benefit. The standard regimen employed was a mixture of physostigmine salicylate (150 micrograms/kg) and artane (trihexyphenidyl hydrochloride 2 mg/kg). Rats were randomly assigned to one of 4 experimental groups: (1) those receiving i.m. sterile saline injection followed 30 min later by s.c. saline injection (normal controls); (2) saline, i.m. followed 30 min later by one of several doses (60-110 micrograms/kg of soman, s.c.; (3) saline, i.m., followed 10 min later by the standard pretreatment regimen i.m., followed by one of several doses of soman (160-300 micrograms/kg), s.c.; and (4) clonidine hydrochloride (1 mg/kg) i.m., followed 10 min later by the pretreatment regimen, followed 30 min later by soman. All animals were examined acutely and survivors were examined over a 3-week period following soman administration. The following observations were made: (1) Addition of clonidine to the standard pretreatment regimen did not enhance survival rate over the standard regimen alone (unless the clonidine was administered after the regimen). (2) Of the acutely toxic behavioral signs promoted by soman, clonidine addition to the standard regimen was of benefit only in reducing soman-induced tremor. (3) Addition of clonidine to the standard regimen appeared to hasten the return to normal motor behavior after soman; however, all groups exhibited normal motor behavior in 9 days. (4) Despite apparent normal motor behavior, soman-treated animals exhibited a marked performance deficit in the passive avoidance parameter 3 weeks after injection. The standard regimen partially preserved this effect; addition of clonidine to the standard regimen completely reversed the effect. These results indicate that clonidine provides a measure of protection against chronic behavioral deficits caused by soman intoxication. 相似文献
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C Schweitzer L T T Vu Y T Nguyen C Choné B Demoulin F Marchal 《The European respiratory journal》2006,28(1):89-95
The bronchomotor effects of a deep inhalation (DI) may provide relevant information about the mechanisms of exercise-induced airway obstruction in children and may be assessed by respiratory conductance (Grs) measured using the forced oscillation technique. The aims of the present study were to assess the effect of DI on Grs after exercise in relationship to the lung function response to exercise. Grs at 12 Hz using a head generator and spirometric data were measured in 62 children suspected of asthma before and 5 min after a 6-min free run. After exercise, Grs was significantly increased by DI in 38 subjects, who also showed larger Grs and forced expiratory volume in one second (FEV1)/forced vital capacity (FVC) responses to exercise than the 24 nonresponders. Stepwise regression indicated significant correlation between the response of Grs to DI and both Grs and FEV1/FVC responses to exercise. The data are consistent with exercise-induced bronchoconstriction being reversed by deep inhalation. 相似文献
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Ki H. Chon Richard J. Cohen Niels-Henrik Holstein-Rathlou 《Annals of biomedical engineering》1997,25(4):731-738
A linear and nonlinear autoregressive moving average (ARMA) identification algorithm is developed for modeling time series
data. The algorithm uses Laguerre expansion of kernals (LEK) to estimate Volterra-Wiener kernals. However, instead of estimating
linear and nonlinear system dynamics via moving average models, as is the case for the Volterra-Wiener analysis, we propose
an ARMA model-based approach. The proposed algorithm is essentially the same as LEK, but this algorithm is extended to include
past values of the ouput as well. Thus, all of the advantages associated with using the Laguerre function remain with our
algorithm; but, by extending the algorithm to the linear and nonlinear ARMA model, a significant reduction in the number of
Laguerre functions can be made, compared with the Volterra-Wiener approach. This translates into a more compact system representation
and makes the physiological interpretation of higher order kernels easier. Furthermore, simulation results show better performance
of the proposed approach in estimating the system dynamics than LEK in certain cases, and it remains effective in the presence
of significant additive measurement noise. 相似文献
5.
Chon D Simon BA Beck KC Shikata H Saba OI Won C Hoffman EA 《Respiratory physiology & neurobiology》2005,148(1-2):65-83
Xenon-enhanced computed tomography (Xe-CT) has been used to measure regional ventilation by determining the wash-in (WI) and wash-out (WO) rates of stable Xe. We tested the common assumption that WI and WO rates are equal by measuring WO-WI in different anatomic lung regions of six anesthetized, supine sheep scanned using multi-detector-row computed tomography (MDCT). We further investigated the effect of tidal volume, image gating (end-expiratory EE versus end-inspiratory EI), local perfusion, and inspired Xe concentration on this phenomenon. RESULTS: WO time constant was greater than WI in all lung regions, with the greatest differences observed in dependent base regions. WO-WI time constant difference was greater during EE imaging, smaller tidal volumes, and with higher Xe concentrations. Regional perfusion did not correlate with WI-WO. We conclude that Xe-WI rate can be significantly different from the WO rate, and the data suggest that this effect may be due to a combination of anatomic and fluid mechanical factors such as Rayleigh-Taylor instabilities set up at interfaces between two gases of different densities. 相似文献
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Modupeola Diyaolu Anne-Laure Thomas Lauren SY Wood Jordan Taylor James CY Dunn 《Journal of pediatric surgery》2021,56(1):5-10
BackgroundShort gut syndrome, a condition characterized by inadequate absorption of nutrients owing to decreased bowel length, has minimal avenues for treatment. We have proposed spring-mediated distraction enterogenesis to lengthen bowel in porcine jejunum as a treatment for short gut. We aim to evaluate the extent of mesenteric neovascularization in segments of lengthened bowel via spring-mediated enterogenesis.MethodsFemale juvenile Yucatan pigs underwent laparotomy and insertion of gelatin-encapsulated compressed nitinol springs, held in place with plication sutures, into the jejunum. At surgery and sacrifice, macroscopic mesenteric blood vessels were counted between the plication sites. Histologic samples of the mesentery were obtained to evaluate microscopic vasculature.ResultsA statistically significant increase in macroscopic mesenteric blood vessels was seen after intestinal lengthening (before: 1.9 ± 0.7 vessels, after: 4.7 ± 1.2 vessels, p = 0.001). A statistical significance is also seen in the density of arterioles (control: 3.0 ± 3.0 vessels/mm, spring: 7.0 ± 9.0 vessels/mm, p = 0.01) and venules (control: 4.0 ± 3.0 vessels/mm, spring: 8.0 ± 8.0 vessels/mm, p = 0.003).ConclusionIntestinal segments lengthened by intraluminal springs demonstrated total greater number of macroscopic vessels and microscopic blood vessels per length of mesentery as compared to control. This suggests local changes within the mesentery to recruit blood supply to growing intestine.Level of evidenceN/AType of studyTreatment study. 相似文献
7.
Biomechanical assessment with electromyography of post-stroke ankle plantar flexor spasticity 总被引:1,自引:0,他引:1
Spasticity has been defined as a motor disorder characterized by a velocity-dependent increase in tonic stretch reflex (muscle tone). Muscle tone consists of mechanical-elastic characteristics, reflex muscle contraction and other elements. The aims of this study were to determine whether to assess spasticity quantitatively, and to characterize biomechanical and electromyographic spasticity assessment parameters. These assessment parameters were described by investigating the correlation between clinical measures and the response to passive sinusoidal movement with consecutive velocity increments. Twenty post-stroke hemiplegic patients and twenty normal healthy volunteers were included in the study. Five consecutive sinusoidal passive movements of the ankle were performed at specific velocities (60, 120, 180, and 240 degrees/ sec). We recorded the peak torque, work, and threshold angle using a computerized isokinetic dynamometer, and simultaneously measured the rectified integrated electromyographic activity. We compared these parameters both between groups and between different velocities. The peak torque, threshold angle, work, and rectified integrated electromyographic activity were significantly higher in the post-stroke spastic group at all angular velocities than in the normal control group. The threshold angle and integrated electromyographic activity increased significantly and linearly as angular velocity increased, but the peak torque and work were not increased in the post-stroke spastic group. Peak torque, work, and threshold angle were significantly correlated to the Modified Ashworth scale, but the integrated electromyographic activity was not. The biomechanical and electromyographic approach may be useful to quantitatively assess spasticity. However, it may also be very important to consider the different characteristics of each biomechanical parameter. 相似文献
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Two girls (a 5 year old and a 21 month old) experiencing mononucleosis syndrome with coincidental human herpesvirus (HHV)-7 and Epstein-Barr virus (EBV) infections are described. One patient had primary HHV-7 infection and reactivated EBV infection. The other had primary HHV-7 and EBV infections. These cases indicated that HHV-7 is capable of inducing infectious mononucleosis-like illness. Multiple herpesvirus infection in one of the patients also suggests that interaction among herpesviruses can occur in vivo. The consequence of this interaction may have clinical implications. 相似文献
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